Ha763 From United States of America, joined Jan 2003, 3548 posts, RR: 6 Reply 2, posted (9 years 5 months 2 weeks 3 days 20 hours ago) and read 4767 times:
The ERJ145 is also available in ER, LR, and XR varients.
It all depends on range. For the 777-200, the base -200 has the shortest range, -200ER more than the base, -200LR the most range. The same goes for the ERJ145. The ER has the shortest range, followed by the LR, topped by the XR.